//https://leetcode.cn/problems/reverse-linked-list/

class Solution {
public:
    ListNode* reverseList(ListNode* head)
    {
        if (head == nullptr || head->next == nullptr) return head;

        auto newhead = reverseList(head->next);
        head->next->next = head;
        head->next = nullptr;

        return newhead;
    }
};